Daewoo Lanos 1.4 saloon / hatchback. For a mint 1999 SE (alloys, electric windows, A/C, etc) private sale, with NCT and maybe tax, full documented service history with receipts, 80 / 90 k miles and thoroughly checked by your mechanic, I'd suggest no more than €900 - €1,000 if its exceptionally good.
The used car prices on some of the web-sites are nothing short of fantasy at around €1,700 - €1,900, and the dealers have them on their hands for ages.
With Opel Astra running gear and mechanics as peelaaa pointed out above, servicing and repairs should be cheap. But if the car (any car in fact) hasn't been looked after it could be a nightmare. You will however, if you buy, be committing yourself to driving it 'til it dies completely.
Best of luck.